1. Field of the Invention
The present invention relates to Multi-Protocol Label Switching (MPLS) Networks; and in particular to monitors that detect actual performance of MPLS networks.
2. Description of the Related Art
Networks of general purpose computer systems and special purpose devices connected by external communication links are well known and widely used in commerce. The networks often include one or more network devices that facilitate the passage of information between the computer systems and special purpose devices.
The Multi-Protocol Label Switching (MPLS) protocol allows the creation of simple high-speed switches, circumventing the processing of more extensive header information in higher level protocols, such as the Internet Protocol (IP). MPLS also provides the ability to support multiple service models, do traffic management, and perform other networking functions, with a relatively simple header. MPLS works by appending an MPLS header containing one or more ‘labels’ called a label stack in front of headers of other higher layer protocols. MPLS is described at the time of this writing in Internet Engineering Task Force (IETF) request for comments (RFC) 3031 and RFC 3032 which can be found at the world wide web domain.ietf.org in files named rfc3031.txt and rfc3032.tx in the file directory named rfc. The entire contents of rfc3031.txt and rfc3032.txt are hereby incorporated by reference as if fully set forth herein.
A service provider (SP) offers MPLS networks to support customers with multiple remote sites connected by networks of one or more SPs. The parameters of the service provided by a SP are spelled out in service level agreements (SLAs). SPs monitor the state of their MPLS networks to verify conformance with the SLAs. The traffic over the SP network used to monitor the state of the MPLS network is called operations, administration and maintenance (OAM) traffic. As the number of nodes in MPLS networks increase, the OAM traffic grows geometrically and has increased a burden on network resources.